Friction clutch



3 Shets-Sheet l F. B. HALFORD FRICTION CLUTCH Filed Oct. 5, 1958 July 30, 1940.

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FRICTION CLUTCH Filed Oct. 3, `1938 3 Sheets-Sheet 2 A Fig. la.

I L 1 L M2,

M M1 M6 7`M7 July 3o, 1940.

F. B. HALFORD FRICTION CLUTCH Filed Oct. 3, 1938 5 Sheets-Sheet 3 AitornegzjF movable parts while the other wall is held from` stitute the driven member of the clutch and this Patented July 30, 1940 UNiTED STATES PATENT oFFlcl-z azoassag FarcrioN CLUTCH Frank Bernard Halford, Edgware, England, as-

signor to D. Napier & Son Limited, London,

England, a company of Great Britain Application october s, 193s, serial No. l233,121 In Great Britain October 6, 1937 9 Claims. This invention relates to friction clutches of the kind in which engagement of the friction memy .the present invention the driving or the drivenmember comprises two separate parts provided lwith friction surfaces and'adapted to be moved axially in opposite directions into engagement with cooperating friction surfaces on the other member, and the liquid chamber is formed between the two parts. Thus, the axial forces exiertedl by the friction surfaces of the two parts constituting one member, on the other member, counterbalance one another.

Preferably one or more members, hereinafter called disengaging members, lare provided which, during operation, apply a disengaging force to the oppositely movable parts by reason of centrifugal force acting on such disengaging members. Thusfor example, the disengaging force may-be applied to each of the oppositely movable partsby a series of balls or rollers each disposed in a slot which, viewed in planes containing the axis of rotation, tapers from a wider part nearer the axis of rotation to a narrower part more remote therefrom, one wall of each slot being constituted by a part which moves axially with the associated one of the oppositely axial movement relative to the casing.

When the two oppositely movable parts condriven member does not normally rotate when the clutchis disengaged, means are provided for ad'- mitting the liquid to the liquidI chamber between the two oppositely movable parts at. a pressure sumcient to cause initial engagement when the driven member is stationary or rotating slowly. In such an arrangement where centrifugally operated members apply the disengaging force, it will b e appreciated that when the driven meinber is stationary or rotating slowly, this disengaging force is absent or small so that the liquid pressure need not be high.

The invention may be applied, for example, t0

a clutch forming partof multiple-ratio transmission gearing. Thus, in the case of two-ratio gearing, the ge aring may comprise driving and driven main shafts and an intermediate layshaft carrying gear wheelsl one of which meshes with a gear wheel connected directly to one of the main shafts, hereinafter termed the driving shaft,

' 'another with a gear wheel connected to the other or driven main shaft through a unidirectional driving device -and a third with a gear wheel adapted to be connected to the driven main shaft through a clutch according to the invention. In such an arrangement the ratios of the gearing for connecting the layshaft to the driven shaft respectively through the unidirectional driving de'- vice and the -clutch'is such that with the clutch engaged the driven part of the unidirectional driving device overruns the driving part thereof whereas when the clutch is disengaged the uni-A directional driving device takes up the transmission lof power through its associated gearing.

Two ,alternative constructions according to the invention are illustrated by way of example in the accompanying drawings; in which- Figure 1 is a sectional side elevation, partly somewhat diagrammatic, of one construction according to the invention as incorporated in tworatio transmission mechanism for driving the rotor of a supercharger from an internal combustion engine, and

Figure'Z is" a similar view to Figure 1 of an alternative construction according to the invention. i In theconstruction illustrated in Figure l, the apparatus comprises a driving shaft A connected to the internal 4combustion engine and carrying a gear wheel A1 which meshes with a -gear wheel B on a layshaft Bicarrying two gear wheels B2,

Y B3 of different diameters.

.constituting the driving member of a unidirectional driving device. 'I'his unidirectional driving device comprises a driving member D in the form ofa hollow boss connected to the gear wheel C and having on its outer surface helical splines D1 by which it 'is connected to an intermediate sleeve member Dz having ratchet teeth D3 on vits end face adapted to engage with ratchet teeth D4 on a disc D5 carried on a boss Di secured to a driven shaft E on which is mounted the impeller E1 of the supercharger. The intermediate member D2 carries friction slippers D't frictionally engaging the innersurfaoe of a drum D8 secured to the boss D6 so that when relative rotation in one direction takes place between the gear wheel C and the shaft E and hence between the intermediate member D2 -and the drum DB, the slippers D", by exerting a frictional drag, cause rotational-A movement of the member D2 on the boss D which. through the helical splines D1, is translated into longitudinal movement of the memberD2 to the right to cause disengagement of the ratchet teeth D2, D4 whereas when relative rotation between the gear wheel C and the shaft E takes piacein the 'opposite direction, the opposite effect is produced to bring the ratchet teeth D3, D4 into posi'- tive driving engagement. so that power is transwalls of the members G4 for thepurpe harn-:1.a

1 te the shaft in.

mitted from the gear wheel C directly to the shaft E.

The gea-r wheel B3 meshes with a gear wheel F freely supported on bearings on the driven shaft E and formed integral with a short hollow shaft F1 which is adapted to be-oonnected to the driven shaft E through a clutch according to the invention. Thus, the short hollow shaft F1 extends into a clutch casing G rigidly secured 'as by a.

key G1 to the driven shaft E and thus constituting the driven member of the clutch. Seciu'ed to the end of the shaft F1 which extends into the casing G is a sleeve G2 the outer surface of which is provided with splines G2 which engage corresponding splines on the inner circumferential surface of two oppositely movable driving clutch members G4 having oppositely coned friction surfacesG11 adapted to engage corresponding friction surfaces on the circumferential wall of the casing G through floating friction linings. The end of the casing G remote from tha-tsecured to theshaft E by the key G1 is supported onabearingGouaxneinberG"rig i cliysecuredV The two clutch members G4 are provided with parts, indicated a't G. which can slide relativelyV to one another and have a'slightclearance be- 4 tween them for the purpose*hereinafterdescribed.v whilev the casing G is provided with ,drain holes G'. Leak passages G10 are also provided in afterdescribed.

Passages H; H1 are provided wherebyv oil can be supplied from the interior of the shaft E to the liquid chamber G11 between the eluteh mem- Formed on opposite ends of the are inclined surfaces J'.v J1 which,` with surfaces respectively on the member G1 andon a 'flange J2, form tapering slots in which lie balls J2 constituting members. The balls J2 will thus be subject to centrifugal force during rotation and will exert .gn the members afor'cej tendingto move them towards one another and thus to cause disengagement of the friction surface G5.

It wm be seen that when liquid' is not being suliplied from the interior of the shaft E through the passages H1, H2 to the chamber G11, this chamberwill empty through the passages G10 and the .space between the parts G.s and the action of the balls Js will then be to maintain the clutch disengaged, whereas when liquid is again supplied to the chamber G11 so as ,substantially to illl` it in spite of the continuous small escape through the passages G10 and thespace between the parts G3, the pressure created in the liquid Vtimes with the annular recess M4.

by centrifugal force will overcome the'4 forceexerted on themembers G4 by the balls J3 and will thus move the members G4 apart to cause engagement of the clutch. 1

`Small grooves, as indicated at G12, are coveniently provided at intervals in the parts of the members G1 which abut aga-inst one another when the clutch is disengaged in order to allowv A and normally pressed to the left by a compression spring K1, this valve having, in addition to ports K2 which, when the valve is moved to the right, 'communicate with the ports H1, portsK3 ,which communicate at all times with ports K4 for supplying lubricating oil to the righthand' set of balls i3 and the inner bearing surface of the part J2. The lefthand set of balls J3 is similarly supphed at au times with lubricating 011 through passages K5.

Means are provided for supplying oil to the interior of the'shaft E atA two different pressures. one pressure being suillcient to cause movement of the valve K to the right into the 'position shown so as. to supply oil to the chamber G11, while the other pressure is such that the valve K moves to the left under the action of its spring K11so that oil is only supplied through the ports K3, K5.

To this end, the interiorv of the shaft E conimlmicates through a passage L with a pipe L1 ileading to a valve casing M in which is disposed handle M2. The rotary valveli/i1 is of cylindrical form, its interior-being directly open at all times to a=high pressure oil supply pipe M3 while an annular groove M4'therein communicates at all timeswlth the oil supply pipe M3, through a pressure-reducing valve M1s which serves to rel duce thepressure from, say, the higher pressure of 50 pounds per square inch to an appreciably lower pressure sich as 10 pounds per square inch. The pressure reducing valve Ms is only diagrammatically illustrated since in itself it forms no -part ofthe invention, being of the known type .wherein the valve is in the form of a' differential piston, the larger face of which is subject to the lower pressure while the smaller face is subject to the higher pressure. Formed in the valve M1 is a portMs communicating with its interior and a longitudinal groove M" cohimxmicating at all .position of, the valve the port Mi communicates with the pipe L1 so that oil at high pressure is supplied to this pipe while in the other position the grooveM'I communicates with the pipe L1 so that oil at lowrpressure is supplied to the With the construction shown it will be seen that on the one hand, with the clutch disengaged, -power will be transmitted from the shaft A through the gearing A1, B, B2, C and the unidirectional driving device to the shaft E, whereas on the. other hand, when the clutch is engaged,

power will be transmit-ted at a higher gear ratio from the shaft A through the gearing A1, B, B3, F

-and the clutch to the driven shaft E, the driven member of the unidirectional driving device then overrunning the driving member thereof.

a rotary valve M1 controlled, for example, by a Y Thus, in one Suitable passages conveniently lead from the interior of the shaft E to the various bearings surrounding this shaft, as indicated at E.

In the alternative construction illustrated in Figure 2, the apparatus comprises a driving shaft A carrying a gear wheel A1 meshing with a gearA wheel B on a layshaft B1 carrying gear wheels B2, B3, as in the construction shown in Figure 1. Moreover, the gear wheel B2 meshes with a gear wheel C connected through a unidirectional driving device to a driven shaft E, as in the construction shown in Figure 1.

In the construction shown in Figure 2, however, the gear wheel B3 meshes with a gear wheel N rigidly secured to the casing N1 of a clutch, whereby the gear wheel N can be connected to the driven shaft E. Thus, in this construction,

the casing N1 of the clutch is provided on its end' ance and thus reduce the clearance at highl speeds. In addition; the members N3 are provided with restricted drain passages N6 and the casing is provided with drain passages N".

'Ihe two members N1 are also provided with inclined surfaces N8 which, with surfaces on members N9 secured'to the shaft E, form tapering slots in which lie balls O which constitute disengaging members which, during rotation, thus exert a force on the members N3 tending to move them towards one another to cause disengagement of the clutch.

As in the construction shown in Figure l, means are provided 'for supplying oil to the liquid chamber N10 between the members N3 through -passages P, P1, this supply being controlled by a valve K constructed and arranged in the same manner as the valve K in the construction shown in Figure 1. Thus, in this construction also, in addition to the ports K2 in the valve through ,which high pressure liquid will iiow to the chamber N1o when liquid is delivered at high Vpressure to the interior of the shaft E, ports -K3 are provided through which oil can flow at all times through passages O2 to the righthand set of balls, passages Ofi being Vprovided for the supply of oil to the lefthand set of balls.

The means for supplying oil respectively at higher and at lower pressure to the interior of the shaft E and for controlling this supply are the same as in the construction shown in Figure 1.

It will be seen that in the construction shown in Figure 2 when the clutch is disengaged, power will be transmitted at the lower gear ratio from the shaft A through the gear wheels A1, B, B2, C

and the unidirectional driving device' to the shaft E, Whereas when the clutch is engaged, power will be transmitted at the higher ratio from the shaft A through the gear wheels A1, B, B3, N and the clutch to the shaft E the driven member of the unidirectional driving device then overrunning the driving member.

Further, in the construction shown in Figure 1,

the supply of oil through the passages K3, K4, K5

will not only lubricate the balls J3 but will also supply lubricant to the friction surfaces during `larly for driving the action of engagement, while similarly in the construction shown in Figure 2, the supply of oil through the passages O2 and O3 will lubricate the balls and supply lubricant to the friction surfaces during engagement.

The general operation of the clutch 'shown in Figure 2 ls the same as that shown in. Figure 1, except that since in Figure 2 the members` N3 between which the liquid chamber is formed rotate with the driven shaft, whereas in the construction shown in Figure 1 the corresponding members G4' rotate with the gear wheel F, the speed of engagement of the clutch may be different. L

It is to be understood that the control of the valve M2 in either of the constructions shown such as that described in the specification of United States of America patent rial No. 109,168.

It will be seen that the arrangement according to the invention provides for the balance of axial thrusts due to liquid pressure in the clutch,

Further, in the transmission mechanism shown, the clutch operates at high speed and with small torque so that it can be light and small.

What I claim as my invention and desire to secure by Letters Patent is:

1. A two ratio transmission gearrnore particularly for driving a super-charger of an internal combustion engine, comprising driving and driven main shafts, an intermediate shaft constituting a layshaft, intermeshing gear wheels constituting multiplying gearing connected respectively to the driving shaft and the layshaft, a unidirectional 'driving device coaxial with the driven shaft application Selwith its driven part connected to such driven of engagement, a liquid chamber a part at least of one'wall of which is constituted by a part of one of thejclutch parts so that liquid pressure created in the chamber by centrifugal force will cause axial movement of such clutch part into engagement with the other clutch part, a passage through which liquid can be supplied to the chamber substantially to fill it and means for controlling thesupply of liquid to the chamber, the ratio of the multiplying gearing connecting the layshaft to the driving part of the unidirectional driving device being lower than that ofthe multiplying gearing connecting the layshaft to the driving part of the clutch.

2. A two ratio transmission gear more particuar super-charger' of an internal combustion engine, comprising driving and driven main shafts, an intermediate shaft constituting` a layshaft, intermeshing gear wheels constituting muliplying gearing connected respectively to the riving shaft and the layshaft, a unidirectional driving device coaxial with the driven shaft with its driven part connected to Such driven shaft, intermeshing gear wheels constituting multiplying gearing and connected re- Cil I ing multiplying gearing connected respectively to `bring these friction surfaces into,y engagement with friction surfaces on the other part, a liquid chamber the end walls of which are constituted by parts of the said two oppositely movable members, a passage through which liquid can be supplied to the chamber substantially to ll it, -and means for controlling the supply of liquid to the chamber, the ratio of the multiplying gearing connecting the layshaft to the driving part of the unidirectional driving device being lower than` that of the multiplying gearing connecting the' layshaft' to the driving part of the clutch.

3. A two ratio transmission gear more particularly for driving a super-charger of an internal combustion engine, comprising driving and driven main shafts, an intermediate shaft constituting a layshaft, intermeshing gear Wheels constituting multiplying gearing connected respectively to the driving shaft and the layshaft, a unidirectional driving device coaxial with the driven shaft with .its driven part connected to such driven shaft,

intermeshing gear wheels constituting multiplying gearing and connected respectively to the layshaft and to the driving part of the unidirectional i driving device, a clutch coaxial with the driven shaft and having its drivenpart connected to such driven shaft, intermeshing gear wheels constitutthelayshaft and to the ,driving part of the clutch, cooperating friction surfaces carried by the driving and- -driven parts of the clutch one of such parts comprising two separate members which` carry friction surfaces and are movable axially 1n opposite directions to bring these friction surfaces into engagement with friction surfaces on the other part, a liquid chamber the endwalls of which are constituted by-parts of the said two oppositely movable members, a passage through which liquid can be supplied to the chamber sub- 'stantially toiill it, means for controlling the supply of liquid to the chamber, a series of disengaging members associated with each' of said oppositely movable members and`each disposed, 'in aslot which-viewed in-cross-sections containing the axis of rotation? tapers from a wider` part nearer the axis to a narrower part` more remote therefrom, one' wall ,Of each slot moving axially with'the associated one ofthe oppositely movable members while' the other lwall is held from axial movement relatively to the ,part of the clutch with whclidthe said oppositely movable members cooperate, the ratio of the multiplying Agearing connecting the layshaft `to the driving part of the unidirectio al driving,

device being lower than that of the. ultiplying gearing connecting the" layshaft to the driving part of the clutch. f

4. A two ratio transmission gear more' particu- .larly for driving'a super-'charger of'an internal combustion engine, comprising driving and driven main shafts, an intermediate shaft constituting a layshaft, intermeshing gear wheels constituting multiplying gearing connected respectively to the driving shaft 'and thelayshaftfa unidirectional- 4 l K driving device coaxial with the driven shaft with its driven part connected to such driven shaft,

' intermeshing gear wheels constituting multiplying gearing and connected respectively to the layshaft and to the driving part of the unidirectional driving device, a.. clutch coaxial with the driven shaft and having its driven part connected to such driven shaft, intermeshing gear wheels constituting multiplying gearing* vconnected respectively to theV layshaft and to the driving part of the clutch, the driving and driven parts of the clutch being axially movable relatively to one another tol bring friction surfaces .into and out of engagement, a liquid chamber a' part of one wall of which is constituted by a part of one of the clutch parts so that liquid pressure created'in the chamber bycentrifugal forcewill cause axial movement of such clutch part into engagement;l with'the other clutch part, a passage through which liquid can be supplied tothe chamber substantial to ll it; means for controlling the nsupply of liquid to the chamber, and means for supplying oil to the friction surfaces rduring the period when engagement is being initiated, the ratio of the multiplying` gearing connecting the layshaft to the driving part of the unidirectional' driving device being lower than that o f the multiplying gearing connecting the layshaft to the driving part of the clutch.

5. A two ratio transmission gear more particularly for driving a super-charger of an internal combustion engine, comprising driving and driven main shafts an intermediate shaft constituting a'layshaft, intermeshing gear wheels constituting multiplying gearing connected respectively to the driving shaft'and the layshaft,- a unidirec( tional driving device coaxial with the driven shaft with its driven part Vconnected to such driven shaft, intermeshing gear wheels constituting multiplying gearing and connected respectively to the layshaft'and to the driving part of the unidirectional driving device, a clutch coaxial with the driven shaft and having its Adriven vpart connected to such driven shaft, intermeshing gear wheels constituting multiplying gearing vconnect- .ed respectively to the layshaftandto the driving part of the clutch, cooperating friction surfaces `carried by the driving and driven parts of the clutch one of such parts comprising two separate members which carry lfriction surfaces and are movable axially in opposite directions .to bring these friction surfaces into engagement vwiththe friction surfaces on' the other part. a liquid chamber the end walls o f which are constituted by. parts of the'said two oppositely movable members, a passage through which liquid can be supplied to the chamber substantially to fill it,means for controlling the supply of liquid to the chamber, a series of jdisengaging membersA associated with leach of the said-oppositely movable members and each disposed in a slot which viewed in cross-sections containing the axisy of rotation, tapers from a widerfpart nearer the axis to a narrower'` part more remote therefrom, one wall of` each slot moving axially vwith the associatedA one of the s aid oppositelymdvable members while the other wall is held `from axial movementl relativelyto the part of the clutch withwhichthe `oppositely movable members -fco operate, means for supplying lubricating oil to the slots containing lthe disengaging membersand means whereby such lubricating oil can flow by centrifugal force from the disengaging members' t'o the said friction surfaces during. the period when engagement is'bei'ng initiated, the ratio of 6. A two ratio transmission fgear more particularly for driving a super-charger of an internal combustion engine comprising driving and driven main shafts, an intermediate shaft' constituting a layshaft, intermeshing gear wheels constitutingmultiplying gearing connected respectively to the driving shaft and the layshaft, a unidirectional driving devicev coaxial with the driven shaft with its driven part connected to such driven shaft, intermeshing gear wheels constituting multiplying gearing and connected respectively to the layshaft and to the driving part of the unidirectional driving devicea clutch coaxial with the driven shaft and having its driven part connected to such driven shaft, intermeshing gear Vwheels constituting multiplying gearing connected respectively to the layshaft and to the driving part of the clutch,cooperating friction surfaces carried by the driving and driven parts of the clutch one of such parts comprising two separate members which carry friction surfaces and are movable axially in opposite directions to bring these friction surfaces into engagement with 7the friction surfaces on the other part, a liquid chamber the end walls of which are constituted by parts of the said two oppositely movable members, a passage through which liquid can be supplied to the chamber substantially to ll it, a valve for controlling the supply of liquid from the passage to the chamber, means for delivering oil to the passage selectively at a higher and lower pressure and means whereby the valve is caused tomove automatically so that when oil is-supplied at the higher pressure the valve moves to permit the supply of oil to the liquid chamber whereas when-the oil is supplied at the lower pressure the valve moves to cut off the supply of oil to the liquid chamber but to maintain the supply of oil for lubricating purposes tothe parts of the clutch, the ratio of the multiplying gearing connecting the layshaft to the driving part of the unidirectional driving device being lower than that of the multiplying gearing connecting the layshaft to the driving part of the clutch. '1. A two ratio transmission gear more particularly for driving a super-charger of internaL combustion engine comprising driving and driven main shafts, an intermediate shaft constituting a layshaft, intermeshing gear wheels constituting multiplying gearing' connected respectively to the driving shaft andthe layshaft. a unidirectional driving device coaxial with the driven shaft with its driven part connected to such driven shaft,

intermeshing gear. wheels constituting multiply-V ing gearing and connected respectively to the layshaft and to the driving part of the unidirectional drivingV device, a clutch coaxial with the driven shaft and having its driven part connected .to such-:driven shaft,r intermeshing gear ultlplylns 'searing 09nnected respectively t the layshaft and tothe driving part of." the clutch, coopera i: friction surfaces carried by the and ven parts of the clutch one of such parts c f separate members which carry friction surfaces and are movable axially in opposite directions to bring these friction surfaces into engagement with friction surfaces on the other part, a liquid chamber the end walls of which are constituted by parts of the said two oppositely movable members, a passage through which liquid can be supplied to the chamber; substantially to fill it,

means for controlling the -supply of liquid from the passage to the chamber, comprising a valve of the piston type, means for supplying high and low pressure oil respectively to the parts of the passage lying on .opposite sides of the valve, a viscous resistance element provided in the passage, serving to control the rate of flow of liquid through thev clutch in accordancewith the viscosity of `such liquid, the ratio of the multiplying gearing connecting the-layshaft to the driving part of the unidirectional driving device being lower than that of the multiplying gearing connecting the layshaft to the driving part of the clutch. f

8. A two ratio transmission gear more particularly for driving a super-charger of an internal combustion engine, comprising driving and driven, m`ain shafts, an intermediate shaft con-y spectively to the driving shaft and the layshaft, a

unidirectional driving device coaxial with the driven vshaft with' its driven part connected to v such driven shaft, intermeshing gear wheels constituting multiplying gearing and connected respectively to-the layshaft and to the driving part of the unidirectional driving device, a clutch coaxial with the driven shaft and having its ldriven part connected to such driven shaft,l intermeshing gear wheels constituting multiplying gearing connected respectively to the layshaft and to the'driving part of the clutch, the driving and drivenparts of the clutch being axially movable re1ativelyi-..to one another to bring friction surfaces intiia'nd out of engagement, a liquid chamber a part at least of one wall of.which is constituted by apart of one of the clutch parts so that liquidV pressure created in the chamber by centrifugal force will cause axial movement of such 4clutch part into engagement with the lother `clutch part, means `for permitting dismovement of the valve to enable oil to pass to the liquid chamber whereas when oil is supplied at Athe lower pressure the valve moves to cut oifl the supply of oil to the chamber while permitting continuance of flow of oil for lubricating purthe unidirectional driving device 1Being lower 

